The present invention relates to the manufacture of rods for use in the manufacture of smoking articles, and in particular to the manufacture of filter rods for cigarette manufacture.
Popular smoking articles, such as cigarettes have a substantially cylindrical rod shaped structure and include a charge of smokable material such as shredded tobacco (e.g., cut filler) surrounded by a paper wrapper, thereby forming a so-called "tobacco rod." It has become desirable to manufacture cigarettes having a cylindrical filter element aligned in an end-to-end relationship with the tobacco rod. Typically, a filter element includes cellulose acetate tow or other material having a continuous integrity circumscribed by plug wrap, and is attached to the tobacco rod using a circumscribing tipping material. Cigarette filter elements are provided by subdividing a filter rod at regular, predetermined intervals. Various types of cigarette filter rod apparatus are known such as described in U.S. Pat. Nos. 4,807,809 to Pryor et al and 4,862,905 to Greene, Jr. et al.
During the manufacture of filter rods using a conventional filter rod-making apparatus, a stream of filter material having a continuous integrity is formed into a rod-like composite and compressed by a constriction member. An exemplary constriction member commonly is known in the art as a "tongue". Should the filter making machine be running at a high rate of speed there is a tendency for frictional forces to build-up on the constriction member particularly due to the accumulation of a gum-like substance on its inner surface. This is sometimes a problem when the rod material has been treated with a smoke-modifying agent (e.g., flavorants, tobacco extracts and the like) such as described in U.S. Pat. Nos. 4,549,875 to Pryor and 4,850,301 to Greene Jr. et al and U.S. Ser. No. 414,835 filed on Sep. 29, 1989. The increase in frictional forces and accumulation of the gum-like substance reduce the efficiency of the machine, and also the uniformity and quality of the rods produced.
Various references have proposed introducing substances in the tongue region of a tobacco rod making apparatus as a stream of a plurality of individual pieces of shreds or strands of tobacco material (i.e., a "tobacco filler material") is formed into a tobacco rod. For example, U.S. Pat. No. 4,186,754 to Labbe proposes feeding water or alcohol to the surface of the tongue which contacts the stream of a particular type of tobacco in order to dilute and reduce the viscosity of gum which reportedly builds up on the tongue. U.S. Pat. No. 4,409,995 to Nichols proposes applying flavorant in particulate or liquid form to a cigarette rod through the tongue region of a tobacco rod making apparatus. U.S. Pat. No. 4,619,276 to Albertson et al proposes applying flavorant in foam form through the tongue region of a tobacco rod making apparatus. U.S. Pat. No. 4,899,765 to Davis et al proposes the application of a liquid fluid to tobacco filler material while in the tongue region of a tobacco rod making apparatus which allows a manufacturer to produce a cigarette rod of controlled integrity.
It would be highly desirable to provide an apparatus for manufacturing filter rods for smoking articles of highly consistent quality and at high speeds.